Method of making raised electrical contact points



G. S. GIBBS METHOD OF MAKING RAISED ELECTRICAL CONTACT POINTS Filed Aug. 5, 1947 Patented Mar. 13, 1951 METHOD OF MAKING RAISED ELECTRICAL CONTACT POINTS 7 George S. Gibbs, Newton, Mass. Application August 5, 1947, Serial No. 766,336 2 Claims. (01. 29 '5.5'5)

My present invention is a novel and improved method of manufacturing various articles utilizing powdered metal under heat and pressure, and is particularly valuable in making electrical contact points, ornamentations for jewelry, and the like. Z ,My invention ,is especially applicable to the manufacture of articles utilizing powdered silver, and comprises improved methods of handling such powdered metal, conserving the quantity of powder necessary in the making of any specific article, insuring uniformity in successive articles and utilizing a novel and improved continuous method of manufacture.

Heretofore it has been customary in the making of electrical contact devices, for example, to utilize silver for the contact points, first forming the silver article into a disc by cutting from a sheet of such metal, or otherwise. Cut and formed base material was utilized with protuberances in which the metal discs were applied, usually by hand, and soldered in place in a furnace. after which thebasematerial was re-struck or coined, thus forcing the metal discs to conform to the protuberances' in the base metal, resulting in a protuberance'c'apped with silver for better operation.

-such'discs and the'pos'itioning of the same on the base material 'wassubject to considerable error and displacement in position, so that the resultant eantaer'iinems cut from the sheet comprising two, three, or more of such contacts lacked uniformity, and also caused unnecessary flow of added material (silver) at the periphery of the protuberance. In my present invention I utilize a powdered metal, such as silver, for the contact points or for the ornamentation desired in jewelry manufacture, and first make the indentations in the base material and then apply a small quantity of the powdered silver into the said indentations, first coating the indentations with a suitable flux to permit the powder to be bonded to the base when sintered and solidified in permanent bond with the base material. Thereupon, after the waste powder has been swept or struck from the top of the indentation and sintered or solidified, the under or reverse side of the base material is punched upwardly or indented from the bottom, thus forming the metal surface in a rounded projecting position for electrical contact use, jewelry ornamentation, or other purposes.

Thus my method enables the powdered silver to be accurately positioned with rounded uniformity to utilize a minimum quantity of the sil- 2 ver powder and to result in a better union of the powdered metal under heat and pressure during the sintering operation and, thus, giving a more permanent bond and union in the fusing of the fiux element with the base material, as well as uniformity in the resultant article made thereby.

In as expensive a material as powdered silver, the saving in the powderitself for such contact points as above described is of great importance and the operation of first indenting a sheet of metal as a base insures the location and position of the silver applied to such indentations. The coining operation also is accurately and effectually performed. Also, my method results in presenting the thickest coating of silver at the crown of the protuberance, and thinning out around the peripherythus increasing wear-resistance at the crown.

While .I prefer to first intent the base, then to apply a coating or fluxing element, and thereafter to supply the powdered silver to the indentations, I may utilize the powdered material with the fluxing element mixed therein and, thus, supply both duringlthe action of filling the indentations. Or Imay utilize. the powder with or without the fiuxing element as a portion of the indenting action. .Thereafter, the sintering operation gives a firm bond and union between the powderedsilver'and the base metal as well also as solidifying the ,powder into a uniform mass. Thereafter, the punchingupwardly of the base metal under each of the silver coated points effects the raising and projecting of the silvered parts into operative or ornamental position, with maximum material at the top of the projection and minimum at the periphery of the projection. Also, I may simply recess the base material and fill the same with powdered metal or silver, compacting it in any desired way, and this feature I wish to claim herein broadly.

Referring to the drawings illustrating my preferred method of manufacture and improved article made thereby:

Fig. l is a diagrammatic view showing a continuous method of operation;

Fig. 2 is an enlarged cross-sectional view of one of the powder-receiving depressions made in the base metal;

Fig. 3 illustrates the filling of such a depression with powder;

Fig. 4 is illustrative of the fusing, solidifying, and sintering of the owdered metal in the depression;

Fig. 5 is a diagrammatic view of the punchin operation forming the previously indented surface thereupon fed thru a station 8 which applies a,

fluxing element Ill, see Fig. 2, as acoating or the like into each of the depressions 6. There;- after, the continuous travel of the base I carries the same with the depressions uppermostby a powder filling station I2, which will flow a suit;- able amount of powdered silver into achbf-the depressions 6 on top of the fiux coating 10- Thereupon, the base I passes by a scraping or cleaningflonerat qn .whereiaa ser es qt ushes or the like, asdndicatq at'jfi, will st s rplusr'powder fr m it. e dams A .l the ow h w at l5 F e- 3 fl sbp evel with the top of the base I Continued travel of the strip I carries the same with the powder the de res inte f n ce .120 whi h t 2 fies ,thepQvJ'deilSQint ,a cfompact In S asi dicated fat "2l, Figract ls'pn the flexing element o hereby .efi tutll b ns m lm tit th l ed PQWdr'fand. t ba w hfb is oneration ould nerma lv e l ght y d ere lsd below the levelof the top of the plate lat each de e san A w ti t nnel i ed at d a :24 O t a th tin ed line tra e lor the e I ith h sinte edmwd md. at theen ed will be sufliciently cooledandset {or subsequent handling. I t d s ra t?- a ee qqntr wh qh is indicated at V2; in advancefof 'tl re feed rollers 26 nd 21 so. that the base! ma b l Qmen any held against cojntinuous feeding motiond ng h pun h n he e s es s p l n th" u in ment ant powde 'tqth r se I'wh r: upon th base l .c n. ints 1v fi Lline o flt a, 1 e sec nd t mp n ss' igiyvihi eflects a reverse punchin o eratiqn "Qt. the recess s 1 p n hi the same into a projectingrecession the opposite side, thus elevatingthes o dified Isilv er'surface 35 t a a s d 19 9 2191 @STSRQWI} atFi 5- P Th s men eras we d t meless v1 can .4 form, and cut oil predetermined shapes or sections from the strip l as indicated at 36; whereupon these sections would travel down the chute 38 and be collected into a receptacle 40. Thus, raised silver surfaced projections or bosses are readily and accurately positioned and produced automatically, and at great speed, entirely independent of manual handling and spotting of discs, as well .as without the skilled labor previously req Us. l

I claim:

'1. Themethod of forming a raised electrical .lnetallic contact point with metallic backing material; which consists in indenting a metal base sheet, applying a coating of flux to the surface .Q-f theindentation, filling the indentation with metal powder, heating the metal powder and the base'sheett'o sinter the metal powders together ,and to bqnd the sintered metal powder to the base sheet, and then reg-indenting the base sheet rqm v12m? 9pm. be u a e te rqduqe a rais e'leetrica spe t, a T e met qd f f rming a ra s dv le ct f al mfia l cieoritact' poir1t1w h meta1 ki g. V

terial, whichcon sists in indfinting .a metal in e sheet, applying 'acoating of 'fiuxto thesurf a ce Qf h i. entation lin theindenta iq wi silver pQ If, heatirithesilver no der and the baseps ee qtoisint r .thej,silv'er".p w ers to a t'wl n t j'si ere 3s 1ve p wder t 1 B base-sheet an-e f i d ntm h basesb rom theq h" esu faceftb titqdiiiqe'ia. raised demise-, q taatin n nti i QEQB E- GIB are? h ie o me t erenccs a e oflrecord i the fil of his p t nt Ul-JlTE-D s'rA rEs ENTS Number Date mages f0, 1912 1,744 510 28 1930 

